<%@page language="java" contentType="text/html; charset=UTF-8"
          pageEncoding="UTF-8"%>

<%
    String callback= request.getParameter("callback");
    if (callback ==null|| "".equals(callback)){
        out.print("{\"abc\":123}");
    }
    else {
        out.print(callback+"({\"abc\":123})");
    }
%>